The needed teachers, managers, construction facilities, and institutions simply do not exist. Without such assimilation, population problems would in no way be ameliorated; they would simply be transferred geographically. Moreover, immigration is almost always differential; the young men, the able, and the venturesome would be the first to migrate, and those who were left behind in the home country would suffer grievously from their loss. A transfer of a much smaller amount of capital than that required for immigrant assimilation from the presently rich countries to the poor ones would probably go much further in bringing about economic and social development of the poor countries, and thereby in creating the conditions for a marked reduction in fertility and the rate of world population growth.
More than a thousand million hectares of arable but uncultivated land exist in North and South America and Africa. The longer the time during which world population continues to increase, the more likely it becomes that there will be no economic alternative to making very large capital investments to bring these areas under cultivation and to settle them with large numbers of people. But for the foreseeable future, food supplies can be increased to match human food needs much less expensively by raising yields and by multiple-cropping on presently cultivated land. Capital for agricultural development will be better spent and new technology more effectively applied on the farms of India and Pakistan, where almost all arable land is already cultivated, than in the sparsely settled parts of countries in which there are large areas of uncultivated arable land.
POPULATION-RESPONSIVE POLICIES CALLED FOR BY HIGH RATES OF FERTILITY AND POPULATION GROWTH
Rates of population growth in less developed countries are at least half, and in some cases almost equal, the rates of economic growth. Chiefly because of the high fertility of these countries, the ratios of children to adults are also very high when compared with these ratios in developed countries, and both the numbers of children and of young people entering the age of labor force participation are rapidly increasing. Because of these factors, planners and political leaders should take future population growth and change into account in all long-range planning. The following are a few examples.
Health and Educational Manpower
The numbers of teachers, physicians, and health workers who need to be trained must be equal to the sum of replacements for those who retire or die, plus additional personnel to keep up with the growing numbers of children in school and the numbers of children and adults requiring health services. If the